Study Reveals the Logic Behind Our Irrational Brains

Is a pound of stones heavier than a pound of feathers? Of course they both weigh the same, but the decisions people make are remarkably susceptible to how choices are presented or framed.

Now scientists are pinning down the centers in the brain related to how this "framing effect" can influence decision-making. The findings could have a big impact on economics, among other things.

"Classical economics assumed humans are fundamentally rational and never really considered emotions quite important, but this shows emotions are embedded in our brain when it comes to making decisions," said Benedetto De Martino, a cognitive neuroscientist at University College London.

How you frame it

De Martino and his colleagues scanned the brains of 20 volunteers. At the same time, the researchers told the participants they received a sum of money and then repeatedly posed them one of two choices. Either the volunteers were told they could keep a chunk of money or gamble, or informed they could lose some fraction or gamble.

As expected, those told they could keep money or gamble were generally leerier of risk. On the other hand, volunteers informed they could lose money or gamble often were more risk-seeking.

The volunteers who were more susceptible to the framing effect showed greater activity in an emotion- and learning-related brain region called the amygdala.

People most immune to this framing effect had increased activity in other brain regions, the orbital and medial prefrontal cortex, "some of the most modern areas of the brain, the most different between us and the other primates," De Martino told LiveScience. When these are damaged, the resulting behavior can be driven completely by emotion and impulse.

Coping with emotions

Emotions can help play a role in decision-making when information is incomplete or too complex, to serve as at times critical rules of thumb, the researchers said in their report in the Aug. 4 issue of the journal Science. However, in modern society, where making the best decision can often require skills of abstraction and examining problems outside their context, emotions can render decisions irrational.

De Martino stressed that people who could overcome the framing effect did not lack emotions.

"Some people think rationality is the opposite of emotion, but from our results, everyone had emotion, but some people were better at coping with their emotions," he explained.

Charles Q. Choi

Charles Q. Choi is a contributing writer for Live Science and Space.com. He covers all things human origins and astronomy as well as physics, animals and general science topics. Charles has a Master of Arts degree from the University of Missouri-Columbia, School of Journalism and a Bachelor of Arts degree from the University of South Florida. Charles has visited every continent on Earth, drinking rancid yak butter tea in Lhasa, snorkeling with sea lions in the Galapagos and even climbing an iceberg in Antarctica.